Why do penguins eat stones?

The meals of Penguins include one item that few species eat on purpose: stones.

In addition to eating fish, krill, crustaceans, and cephalopods, Penguins eat small rocks that help them better digest their food, researchers theorize. The process is nothing new. After all, dinosaurs appear to have done the same thing.

These small stones that are purposeful eaten are called “gastroliths” and have been found in dinosaur fossils.

Researchers also theorize the gastroliths help the birds dive deeper for foods by providing extra weight.